Translation: "One sees, from this Essay, that the theory of probabilities is basically just common sense reduced to calculus; it makes one appreciate with exactness that which accurate minds feel with a sort of instinct, often without being able to account for it."

From the Introduction to Théorie Analytique des Probabilités, second and later editions; also published separately as Essai philosophique sur les Probabilités (1814). Œuvres complètes de Laplace, tome VII, p. cliii, Paris: Gauthier-Villars, 1878-1912.

Also reported as: "The theory of probabilities is at bottom nothing but common sense reduced to calculus; it enables us to appreciate with exactness that which accurate minds feel with a sort of instinct for which ofttimes they are unable to account."

Or as: "Probability theory is nothing but common sense reduced to calculation."

Translation: "What we know is not much. What we do not know is immense."

Allegedly his last words, reported in Joseph Fourier's "Éloge historique de M. le Marquis de Laplace" (1829) with the comment, "This was at least the meaning of his last words, which were articulated with difficulty." Quoted in Augustus De Morgan's Budget of Paradoxes (1866).

"L'homme ne poursuit que des chimères."

Translation: "Man follows only phantoms."

His true last words, according to Augustus De Morgan's Budget of Paradoxes (1866).

Compare Edmund Burke's famous remark, after a parliamentary candidate's sudden death, about "what shadows we are, and what shadows we pursue".

"Lisez Euler, lisez Euler, c'est notre maître à tous."

Translation: "Read Euler, read Euler, he is the master of us all." (Sometimes freely translated as: "Read Euler: he is our master in everything.")

Laplace made many important discoveries in mathematical physics... Indeed, he was interested in anything that helped to interpret nature. He worked on hydrodynamics, the wave propagation of sound, and the tides. In the field of chemistry, his work on the liquid state of matter is classic. His studies of the tension in the surface layer of water, which accounts for the rise of liquids inside a capillary tube, and of the cohesive forces in liquids, are fundamental. Laplace and Lavoisier designed an ice calorimeter (1784) to measure heat and measured the specific heat of numerous substances; heat, to them, was still a special kind of matter. Most of Laplace's life was, however, devoted to celestial mechanics.

Morris Kline, Mathematical Thought from Ancient to Modern Times (1972)

Laplace created a number of new mathematical methods that were subsequently expanded into branches of mathematics, but he never cared for mathematics except as it helped him to study nature.

Morris Kline, Mathematical Thought from Ancient to Modern Times (1972)

This is another important dispute in the history of how we think about being wrong: whether error represents an obstacle in the path toward truth, or the path itself. The former idea is a conventional one. The latter... emerged during the Scientific Revolution and continued to evolve throughout the Enlightenment. But it didn't really reach its zenith until the early nineteenth century, when... Pierre Simon Laplace refined the distribution of errors, illustrated by the now-familiar bell curve. ...Laplace used the bell curve to determine the precise orbit of the planets. ...By using the normal distribution to graph... individually imperfect data points, Laplace was able to generate a far more precise picture of the galaxy. ...aggregate enough flawed data, and you get a glimpse of the truth.

Laplace had taken Newton's science and turned it into philosophy. The universe was a piece of machinery, its history was predetermined, there was no room for chance or for free will. The cosmos was indeed an ice-cold clock.

Reputed reply to Emperor Napoleon I, who had asked why he hadn't mentioned God in his discourse on secular variations of the orbits of Saturn and Jupiter ("Mais où est Dieu dans tout cela?"/'But where is God in all this?').